In the modern manufacturing workplace, individual workers are often required to perform repetitive tasks while positioned at a specific location. The worker may have a particular work surface at which to perform the repetitive task. The manufacturing facilities often operate continuously with one or more worker at each work station during each shift of operation. A particular work station work surface may not be suited to the stature of all works who perform tasks at that station. When performing repetitive tasks, such as handling heavy work pieces, the worker may experience physical discomfort or injury when the work surface is not matched to the stature of that worker. Providing a customized work surface for each worker at a work station is economically prohibitive. Thus, there is an unmet need for a device which can be individually adjusted for the needs of each worker who performs tasks at a particular work station work surface.
A number of patents concerned with devices that can adjust the height of a work surface or similar structure have been granted.
Feiertag, in U.S. Pat. No. 3,820,176, discloses a patient handling table that employs a combination of a hydraulic cylinder and cable with pulleys to raise, lower and tilt the table to from end to end.
Hinman, in U.S. Pat. No. 3,827,663, shows a spring loaded, self adjusting furniture support to accommodate uneven surfaces.
Dufrancatel, in U.S. Pat. No. 4,396,222, discloses a trailer with adjustable interior components.
In U.S. Pat. No. 4,441,432, Carlton shows a tilting table top with pins mounted in horizontal slots and in angled slots with notches to allow tilting of the table top.
Vertically adjustable tables are disclosed by de la Haye in U.S. Pat. No. 4,615,279 and by Peterson et al in U.S. Pat. No. 4,828,208. Both patents describe mechanical gearing to adjust a table top surface.
In U.S. Pat. No. 4,944,366, Pryor et al. disclose a pneumatic operated scaffolding to lift sheet rock for ceiling joist attachment. The scaffolding contains four legs with pneumatic cylinders for raising a work support frame. The pneumatic cylinders are removable from the support frame for transport.
U.S. Pat. No. 5,531,413 by Wolf et al. discloses a pneumatic or hydropneumatic length adjusting cylinder for chairs, tables and the like, designed to prevent twisting.
Jonker, in U.S. Pat. No. 5,598,788, describes an adjustable height table with two leg supports. Each leg has a gas spring that resists movement and a ratcheting latch mechanism to maintain a selected table height.
In U.S. Pat. No. 5,615,451, Peterson et al. describe a roller assembly that pivots between up and down positions to elevate or lower an attached table. The roller assembly allows the table to be rolled between locations and set in position with the roller assembly retracted.
In U.S. Pat. No. 5,161,868, Hooser discloses a telephone table with locking casters and means for elevating the table top. The elevating means may be four electrical stepping motors, each of which rotate a threaded shaft in one leg, or a central hydraulic lift cylinder with four hydraulic power cylinders for tilting the table top. The hydraulic system requires an electrical pump to power the system. The stepping motors are controlled in pairs to allow the table top to be tilted from front to back.
Zeiner, in U.S. Pat. No. 5,437,236, describes a rectangular table with a similar base support. A central cylindrical support is fitted with an air pump to cause the cylinder to elevate the table top. Two to four telescoping legs, each with set screws, are positioned to support the table top.